treated lumber question

[David Prince]

Treated lumber needs special screws and nails, correct?

If a person is building a garage on a slab of concrete then the bottom plate would be treated.

I am curious if everyone switches to a proper galvanized fastener when nailing on a treated bottom plate, nailing hangers on treated lumber, nailing joists onto a treated plate, or when you nail your bottom row of nails on your sheathing that goes into the bottom plate.

The previous treated lumber didn't eat fasteners like the new stuff.

Is this a weak link in the constuction process if people do it wrong or is it just over-rated.

[Randy Walton]

The newer forms (safer) are far more corrosive on metals and fasteners than the older arsenic based treatments.
1. Yes you do need special fasteners, the one fastener that is always acceptable is stainless steel.
2. Yes, wood in contact with a slab floor should be treated.
3. If inspectors are doing their jobs, all contractors should be using the appropriate fasteners when attaching fastners or hardware to treated lumber. Doesn't mean that some don't get by without it.....however it Will be a problem.
4. You're correct, the arsenic based treated lumber did not effect fasteners like the newer (safer) treatments.
5. The weak link will be construction failure should contractors ignore the requirements when fastening to ACQ treated lumber.

The are all kinds of facts available on the net regarding pressure treated lumber. Osmose is one of the leadiers in the industry. Check it out.

[Brice Burrell]

David, I'm do residential remodeling and I work with treated lumber fairly often and I always use hot dipped galvanized nails or stainless steel screws. It's just not worth the risk of structural framing failing to saving a few bucks on fasteners.

[Curt Harms]

that mentions alternative treatments that are no more corrosive than CCA. http://www.finehomebuilding.com/how-to/departments/cross-section/more-choices-for-durable-decks.aspx. I haven't seen them in the borgs. Are they more expensive? The purewood process that is just heating enough to convert sugars & starches to compounds unusable by mold & fungi seems interesting in that there are no toxic materials used.

[Jamie Buxton]

... The purewood process that is just heating enough to convert sugars & starches to compounds unusable by mold & fungi seems interesting in that there are no toxic materials used.....

Interesting. I hadn't heard of that before. However, they're marketing the stuff only for decking. In terms of resistance to rot and insects, that isn't as challenging as putting the product against concrete or in the ground. Pressure-treated lumber handles those applications. Purewood apparently doesn't.

[Joe Chritz]

Treated lumber needs special screws and nails, correct?

Yes

If a person is building a garage on a slab of concrete then the bottom plate would be treated.

Yes

I am curious if everyone switches to a proper galvanized fastener when nailing on a treated bottom plate, nailing hangers on treated lumber, nailing joists onto a treated plate, or when you nail your bottom row of nails on your sheathing that goes into the bottom plate.

People do all kinds of things out of greed, ignorance, apathy or a combo of all them.
The previous treated lumber didn't eat fasteners like the new stuff.

Correct but it still would, it just took longer.

Is this a weak link in the constuction process if people do it wrong or is it just over-rated.

What could possibly be bad about nails on joist hangers failing or a wall not having lateral support at the base anymore? The nails for the bottom of the sheathing probably aren't a huge issue since the penalty for failure is low but having some structural element fail is bad juju.



Stainless is the way to go for any critical application.

Joe

[Doug Carpenter]

My drywaller had a house built and used an amish crew to frame it instead of me because it was cheaper. He hired me to do the trim and install the composit decking on the second story deck they had framed while framing the house.

They used regular fasteners for everything and by the time I got there to do my part the fasteners were already rusted pretty heavily.

He sold the house before he moved in because he was over budget so I never heard if the deck fell off. It will sooner or later though.

We always use fasteners for the treated lumber to prevent call backs. Once I forgot and we went back and toenailed all the studs to the bottom plate when we finished.

In the years to come ther is going to be lots of repair work for remodelers because I think many carpenters ignore it. Especially the subcontractors that are already getting killed by the national builders.

Reminds me of a builder I worked for in GA. He hated seeing all the nails laying around the jobsites so he gave the framers an allowance for nails per house. The used one nail at the top of a stud and one at the bottom. I guess they thought the could get rich that way.:eek: You go into any one of the 200 homes a year they build and spin the studs!

[Kent A Bathurst]

For over 50 years, the bulletproof, one-size-fits-all standard for pressure treating lumber was CCA [chromated copper arsenic]. Some years back, there was a huge hoo-hah over the arsenic component. The Bix Box stores didn't really care what the treating chemical was, as long as everyone had to switch at the same time - avoiding a cost advantage to any retailer that stayed with CCA. The EPA, in a classic bureaucratic move of "you can't get in trouble if you do not act" decided to finesse the issue by simply not acting on the renewal of the license for CCA to be used.

Everyone was happy, ACQ became the primary chemical, and costs went up to the consumer due to higher production costs in both chemical and production process time, higher transportation costs because the chemical was much more dilute, meaning multiple truckloads to replace one truckload of the CCA concentrate - and the fact that ACQ was more corrosive and required more costly fasteners + hardware. In the cold, sober, light of dawn - when actual science was used - the entire CCA thing was a cloud of smoke. There were no increased health risks from CCA versus other chemicals. No increased concentration of arsenic from leaching. Don't eat it. Don't breath the dust. Don't burn it (chemicals released in the smoke). Toss scraps in the trash for the landfill.

This area is constantly in a bit of flux - many producers now use Copper Azole (CA) because the chemistry and processing have caught up in the past couple years. I expect that there will continue to be changes in the chemistry and processing, as the industry continues R+D to create new chemicals and processes - to get back to where they were over 50 years ago.

You can never go wrong using stainless steel. OTOH, the cost difference between stainless and galvanized can be substantial (if you ahve a large project) and the stainless is not required for Micro CA or CCA.

And - yes - the punch line: CCA is still produced (although on a limited basis) and still permitted for certain applications. Acricultural (fence posts, pole barns, etc). Full wood foundations. Treated plywood. Why? Nothing else performs like CCA.


An earlier post referred to Osmose. They are the largest producer of chemicals used for pressure treating lumber. They sell to the people that do the actual pressure treating and supply PT lumber to the retailers. From the website of the largest producer of pressure treated lumber, on the topic of fasteners:

Micro CA is less corrosive to fasteners, exhibiting corrosion rates similar to CCA-treated wood and untreated wood. Two studies conducted by Timber Products Inspection Agency and two additional studies by the State University of New York concluded that wood treated with micronized copper is less corrosive than wood treated with soluble copper based wood preservatives.

[David Prince]

A person can get a galvanized version for a nail gun, but the cost is about twice the price of regular 16s. With that, you could choose to nail your entire project with the galvanized version or have two framing nail guns available. One loaded with the galvanized version for the treated lumber issues and the other for general framing.

In the long run, maybe an investment in another framing gun would pay for itself and run two guns, but it would probably take about 10 boxes of nails before you would reach that price point.